Table of Contents
Advertisement
6E–566
TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
ignition ON, engine not running or at wide-open throttle
(low vacuum).
The MAP sensor is used to determine the following:
D Manifold pressure changes while the linear EGR flow
test diagnostic is being run. Refer to DTC P0401 .
D Engine vacuum level for other diagnostics.
D Barometric pressure (BARO).
If the PCM detects a voltage that is lower than the
possible range of the MAP sensor, DTC P0107 will be set.
A signal voltage higher than the possible range of the
sensor will set DTC P0108. An intermittent low or high
voltage will set DTC P1107, respectively. The PCM can
detect a shifted MAP sensor. The PCM compares the
MAP sensor signal to a calculated MAP based on throttle
position and various engine load factors. If the PCM
detects a MAP signal that varies excessively above or
below the calculated value, DTC P0106 will set.
Powertrain Control Module (PCM)
The powertrain control module (PCM) is located in the
passenger compartment below the center console. The
PCM controls the following:
D Fuel metering system.
D Transmission shifting (automatic transmission only).
D Ignition timing.
D On-board diagnostics for powertrain functions.
The PCM constantly observes the information from
various sensors. The PCM controls the systems that
affect vehicle performance.
diagnostic function of the system.
operational problems, alert the driver through the MIL
(Check Engine lamp), and store diagnostic trouble codes
(DTCs). DTCs identify the problem areas to aid the
technician in making repairs.
PCM Function
The PCM supplies either 5 or 12 volts to power various
sensors or switches. The power is supplied through
resistances in the PCM which are so high in value that a
test light will not light when connected to the circuit. In
some cases, even an ordinary shop voltmeter will not give
055RW004
The PCM performs the
It can recognize
an accurate reading because its resistance is too low.
Therefore, a digital voltmeter with at least 10 megohms
input impedance is required to ensure accurate voltage
readings. Tool J 39200 meets this requirement. The PCM
controls output circuits such as the injectors, fan relays,
etc., by controlling the ground or the power feed circuit
through transistors or through either of the following two
devices:
D Output Driver Module (ODM)
D Quad Driver Module (QDM)
PCM Components
The PCM is designed to maintain exhaust emission levels
to government mandated standards while providing
excellent driveability and fuel efficiency.
monitors numerous engine and vehicle functions via
electronic sensors such as the throttle position (TP)
sensor, heated oxygen sensor (HO2S), and vehicle
speed sensor (VSS). The PCM also controls certain
engine operations through the following:
D Fuel injector control
D Ignition control module
D ION sensing module
D Automatic transmission shift functions
D Cruise control
D Evaporative emission (EVAP) purge
D A/C clutch control
PCM Voltage Description
The PCM supplies a buffered voltage to various switches
and sensors. It can do this because resistance in the
PCM is so high in value that a test light may not illuminate
when connected to the circuit.
voltmeter may not give an accurate reading because the
voltmeter input impedance is too low. Use a 10-megohm
input impedance digital voltmeter (such as J 39200) to
assure accurate voltage readings.
The
input/output
devices
analog-to-digital converters, signal buffers, counters,
and special drivers. The PCM controls most components
with electronic switches which complete a ground circuit
060RY00019
The PCM
An ordinary shop
in
the
PCM
include
Advertisement
Chapters
Table of Contents
Troubleshooting
